I had my air ducts cleaned out professionally 4 years ago when I bought my house. I watched the guy clean it with a rotating brush (about 4 inches diameter) hooked up to a vacumn cleaner. It was maybe about 10-15 feet long and he pushed it up in to each vent.

Has anyone attempted to try and clean vents themselves?

I saw this on a plane ride home and was thinking of doing it myself.

http://www.skymall.com/webapp/skystore?process=prodDisplay&action=&pid=85547181&catId=Search